Resistor grid



F. T. COPE RESISTOR GRID June 24, 1930.

2 Shets-Sheet 1 Original Filed Sept. 1 1925 F. T. COPE RESISTOR GRID June 24, 1930.

Original Filed Sept. 17, 1923 2 Sheets-Sheet '2 Fran/i humanism, 930

UNI-TED s'rArss PATENT OFFICE 1'. corn, or sham, onro, assrenon 'ro THE nmcraro rumucn courm,

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Original application filed September 17, 1928, Serial 1m. 663,275. Divided 13', mo. Serial No. 451,916.

' This invention relates to electric furnaces and more particularly to the resistance elements for producing the heat in the furnace and has for its objects to provide a resistor heating grid for'med of solid metal of a cross sectionalshape to radiate the heat rays into the interior of the furnace at an angle to the furnace wall, and comfrising a single bar bent into a plurality 0 parallel sections so proportioned as to produce a radiating surface considerably greater than the wall surface covered by the grid, means being provided for supporting the grid spaced from the furnace wall and in a manner to (permit expansion and contraction of the gri without allowing the sections thereof to move out of their parallel relationto I each other.

The above and other objects may be attained by constructing the resistor grid and sup orting means in the manner illustratedin t e accompan 'ng drawings, in which- Figure 1 is a ront elevation of a resistor grid embodying one form of the invention, showin the same mounted upon a fragment 0 furnace wall;

Fig. 2, a section of the grid on the line 2-2, Fig. 1;

Fig. 53, a section of the so Fig. 4, a section of the grid on the line 4-4, Fig. 1;

Fig. 5, a transverse sectional view through the wall showing an end elevation of the grid and the terminal thereof;

Fig. 6, a perspective view of the terminal stu Fig. 7, a front elevation of the terminal; Fig. 8, a perspective view of one of the grid on the line 40 sup orting hooks,

1g. 9, a similar view of, one of the lower spacing hangers; and

Fig. 10, the modified cross section of the grid, comprising the subject matter of this divisional application.

Similar numerals refer to similar parts throughout the drawings. v

A portion of a furnace wall built of refractory brick or the like, is indicated at 1 and the resistor grid is formed of a conand this application fled lay tinuous bar of metal bent at intervals to produce a plurality of vertical parallel portions 2 of the general cross sectional shape shown in Fig. 3, the curved u ,per ends thereof being preferably fiattene as shown I ati, giving the cross sectional shape shown in Fig. 2,'while the lower curved ends are provided with the depending studs 5.

The resistor grids ma be made of cast, rolledor forge metal are of substantial 6o thickness, .as shown in'the drawing, ,and the general. cross sectional shape 'of the grid may be T-shap'ed, as shown in Fig. 3, the base 6 having the inclined side edges 7, while the flange or rib 8 is tapered toward its point'which is rounded as at 9.

It has been found, however, that a better casting can be made by providing two ribs, one at each side of the base, which also gives a greater radiatingsurface on the ribbed side of the grid, so thata preferred general cross sectional shape of the grid is substantially channelshape, as shown in Fig. 10, the base 6 and the flanges or ribs 8* having inclined sides; and in either case the grid bar being flanged or ribbed to give it strength and rigidity.

With such cross sectional shape, the greater portion of the surface of. the grid is located at an angle to the normal plane of so the grid, thus radiating the majority of the heat rays into the heating chamber of the furnace at an angle to the furnace wall.

Thegrid is supported at its upper edge portion by the hooks 10 which engage the flattened portions 4 of the grid. Each hook is provided with the flattened shank 11 received in the fiat socket 12 formed in the upfper edge of the adjacent brick in the re ractory wall 1, and depending lugs 13 and 1 4 are provided atthe forward and rear ends of the shank to prevent longitudlilnal movement of the shank within the wa The depending. studs 5 upon the lower ends of the grid bars are extended through the squared apertures 15 formed in the lower su ports 16, which are also provided with the flat shanks 17 received in the notches 18 in the upper faces of the adjacent bricks. 109

A shoulder 19 is formed at the inner end of the shank and a depending lug 20 at the outer end thereof to prevent ongitudinal movement of the support in the wall.

Each extremity o the id is connected to a terminal stud 21 w ich is extended througha suitable opening 22 in the brick wall of the furnace, the inner end thereof being rovided with the flat head 23 which is wel ed to the adjacent extremity of the id. A terminal 24 is connected to the outer end of each of the terminal studs 21, having the split socket 25 which receives the end of the stud, clamping bolts 26 clamping the same tightly upon the stud. Sockets 27 are formed in the terminal into which the ends of the cables 28 are soldered or otherwise connected.

Owing to the cross sectional shape of the grid and the conformation of the same, the radiating surface of the grid is equal to about twice the area of wall surface upon which the grid is mounted, thus producing a maximum of heat from a given area.

By referring to Figs. 3 and 10, it will be seen that the cross sectional shape of the grid is such that the greater portion of the radiating surface is arran ed to radiate the heat rays inward toward t e interior of the heatin chamber of the furnace, and away from t e furnace wall at an anglethereto, thus radiating considerably more heat into the interior of the heating chamber than is possible with the usual constructions now in use.

As the studs 5 upon the lower ends of the grid bars are extended loosely through the openings 15 in the lower supports, the grid may expand as the temperature of the same is increased, without causing any buckling or warping, since the entire weight of the grid is supported from the upper hooks.

The upper hooks engagin the loops at the upper end of the grid an the lower supportsengaging the studs upon the lower ends of the grid bars, prevent lateral distortion of the grid under high temperature,

thus preventing adjacent portions of the grid from coming into contact with each other when the are expanded by the heat.

The broad c aims for the neric inven- -tion illustrated and described in said parent but, not claimed herein, are made the subject of claims in the parent application, Serial No. 663,275, from which the application is divided.

I claim 1. A resistor heating grid formed of a bar of substantial thickness of substantially channel shaped, cross sectional shape, bent upon itself to provide a plurality of vertical parallel portions connected at alternate ends y curved portions.

2. A resistor heating grid formed of a bar of substantial thickness of substantially channel shaped, cross sectional shape, bent upon itself to provide a plurality of vertical parallel portions connected at alternate ends curved portions, the curved portions at t e upper end of the grid being of substantiall at cross sectional shape and su porting ooks engaging said upper curve portions.

3. A resistor heating grid of the character described formed of a bar of substantial thickness of substantially channel shaped, cross section, the side faces thereof being inclined to radiate the n'ia'or portion of the heat rays away from the ase in the direction of the ribbed side of the bar.

4. A resistor heating grid for a furnace away from the furnace wall at an angle thereto.

5. A resistor heating grid for a furnace wall comprising a metal bar of substantial thickness bent upon itself at intervals, the convolutions being so spaced and the bar being of substantially channel shaped cross sectional shape, with its sides inclined so as to provide a radiating surface which will radiate the majority of the heat ra s toward the interior of the heating chain r of the furnace and of greater area than the wall Surface covered by the grid.

6. A metal bar resistor heating grid of substantial thickness for electric furnaces consisting of a sinuous grid having straight legs of ribbed section connected at alternate ends by integral loops, some at least of said loops having integral prongs extending outwardl therefrom.

7. 1 metal bar resistor heating grid of substantial thickness for electric furnaces consisting of a sinuous grid having straight legs of ribbed section connected at alternate ends by integral loops.

8. A resistor heating grid made of bar metal of substantial thickness in serpentine shape, the body of the same including a base section and a longitudinal rib projecting from one side thereof.

9. A resistor heating grid made of bar metal of substantial thickness and including a base section and a longitudinal rib projecting from one side thereof.

10. A resistor heating grid formed of a metal ribbed bar of substantial thickness bent upon itself to provide a plurality of vertica nate ends by curved portions.

11. A resistor grid comprising a bar bent upon itself to form a plurality of parallel straight portions, means for supporting the grid at its upper end, dependin studs upon the lower end of the grid an supporting guides provided with apertures loosely engaging the depending studs.

12. A resistor grid for a furnace wall comprising a solid metal bar of such cross sectional shape with its sides inclined so as to provide a radiatin surface which will radiate the ma'or portion of the heat rays away from the urnace wall at an angle thereto.

13. A resistor grid for a furnace wall comprising a solid metal bar bent upon itself at intervals, the convolutions being so spaced and the bar being of such cross sectional shape with its sides inclined so as to provide a radiating surface which will radiate the majority of the heat rays toward the interior of the heating chamber of the furnace and of ater area than the wall surface covered the grid.

In testimony that I claim the above, I have hereunto subscribed 111 name.

FRAN T. corn.

parallel portions connected at alter 

